Frames of reference Knowledge-Based Download PDF

Questions

1. 1.

   Under what condition is a moving object X at rest in the reference frame of another moving object Y?

   • A) When both objects travel at the same speed, regardless of their directions of motion.
   • B) When both objects travel with the same velocity, having identical speeds in the same direction.
   • C) When both objects maintain a constant non-zero acceleration along the same line of motion.
   • D) When the straight-line distance between both objects increases at a steady, constant rate.
2. 2.

   On an airport moving walkway traveling forward at 1.2 m/s relative to the terminal, Passenger X stands stationary on the belt while Passenger Y walks forward at 1.5 m/s relative to the belt. What is the speed of Passenger Y in the frame of reference of Passenger X?

   • A) 1.5 m/s
   • B) 2.7 m/s
   • C) 0.3 m/s
   • D) 0 m/s
3. 3.

   Rain falls vertically downward relative to the ground. In the frame of reference of a car traveling forward along a straight, horizontal road, in what direction do the raindrops appear to fall?

   • A) Diagonally downward and forward
   • B) Diagonally downward and backward
   • C) Vertically downward
   • D) Horizontally backward
4. 4.

   A passenger walks forward along the aisle of a passenger train that is traveling forward at a constant speed along a straight track. Over the same time interval, how does the distance traveled by the passenger in the reference frame of the train compare to that in the reference frame of the ground?

   • A) It is greater in the reference frame of the train than in the reference frame of the ground.
   • B) It is the same in both reference frames because the time interval is identical.
   • C) It is less in the reference frame of the train than in the reference frame of the ground.
   • D) It is zero in the reference frame of the train because the passenger remains inside the train.
5. 5.

   A reference frame $S'$ moves along the $x$-axis at a constant velocity $v$ relative to a reference frame $S$. If the origins of both frames coincide at time $t = 0$, which expression gives the position coordinate $x'$ of a particle in frame $S'$ in terms of its position coordinate $x$ in frame $S$ and time $t$?

   • A) $x' = x + vt$
   • B) $x' = vt - x$
   • C) $x' = x - vt$
   • D) $x' = x + \frac{1}{2}vt$
6. 6.

   Two cars, X and Y, travel along a straight road. A stationary observer on the sidewalk and a moving observer in a third vehicle both measure the velocity of Car X relative to Car Y. Which statement correctly compares their measurements?

   • A) The stationary observer measures a greater relative velocity because the ground is an absolute frame of reference.
   • B) The moving observer measures a greater relative velocity due to the contribution of their own vehicle's speed.
   • C) Both observers measure the exact same velocity of Car X relative to Car Y.
   • D) The relative velocity measured by each observer depends on their distance from Car X.
7. 7.

   A toy car completes one full lap around a closed circular track, returning to its exact starting point on the room's floor. How does the displacement of the car in the reference frame of the floor compare to its displacement in the reference frame of an observer walking across the room at a constant velocity?

   • A) The displacement is zero in both reference frames because the car finishes where it began on the track.
   • B) The displacement is zero in the floor's reference frame, but non-zero in the walking observer's reference frame.
   • C) The displacement is non-zero in the floor's reference frame, but zero in the walking observer's reference frame.
   • D) The displacement is non-zero and identical in magnitude in both reference frames because displacement is an absolute quantity.
8. 8.

   A traffic sign is fixed to the ground along a straight highway. A truck travels at a constant velocity of 22 m/s due east relative to the ground. What is the velocity of the traffic sign in the reference frame of the truck driver?

   • A) 22 m/s due east
   • B) 22 m/s due west
   • C) 0 m/s
   • D) 44 m/s due west
9. 9.

   An escalator moves upward at a constant speed of 0.8 m/s relative to the building. If a person walks downward on this moving escalator at a speed of 0.8 m/s relative to the escalator steps, what is the velocity of the person relative to the building?

   • A) 0 m/s (the person remains stationary relative to the building)
   • B) 1.6 m/s upward relative to the building
   • C) 1.6 m/s downward relative to the building
   • D) 0.8 m/s downward relative to the building
10. 10.

    A boat travels due east at 4.0 m/s relative to the water in a river flowing due north at 3.0 m/s relative to the bank. What is the speed of the boat relative to the riverbank?

    • A) 1.0 m/s
    • B) 3.5 m/s
    • C) 5.0 m/s
    • D) 7.0 m/s
11. 11.

    According to classical kinematics, if a particle has velocity $\vec{v}_{P/A}$ relative to reference frame A, and frame A moves with velocity $\vec{v}_{A/B}$ relative to reference frame B, which expression correctly gives the velocity $\vec{v}_{P/B}$ of the particle relative to frame B?

    • A) $\vec{v}_{P/B} = \vec{v}_{P/A} - \vec{v}_{A/B}$
    • B) $\vec{v}_{P/B} = \vec{v}_{A/B} - \vec{v}_{P/A}$
    • C) $\vec{v}_{P/B} = \vec{v}_{P/A} + \vec{v}_{A/B}$
    • D) $\vec{v}_{P/B} = \frac{\vec{v}_{P/A} + \vec{v}_{A/B}}{2}$
12. 12.

    Two observers set up one-dimensional coordinate systems along the same straight track to monitor a moving cart. Observer 1 defines the positive direction to the right, whereas Observer 2 defines the positive direction to the left. When the cart moves 12 m to the right, which displacements do the two observers record?

    • A) Observer 1 records -12 m, and Observer 2 records +12 m.
    • B) Observer 1 records +12 m, and Observer 2 records +12 m.
    • C) Observer 1 records -12 m, and Observer 2 records -12 m.
    • D) Observer 1 records +12 m, and Observer 2 records -12 m.
13. 13.

    Which of the following represents a non-inertial frame of reference?

    • A) A bus rounding a curve at a constant speed
    • B) An airplane cruising along a straight path at a constant speed
    • C) A cart resting motionless on a level table
    • D) A train moving along a straight track at a constant velocity
14. 14.

    Two cars travel along a straight road in opposite directions: Car X moves east at 25 m/s relative to the ground, and Car Y moves west at 15 m/s relative to the ground. What is the velocity of Car X as observed from the reference frame of Car Y?

    • A) 10 m/s to the west
    • B) 10 m/s to the east
    • C) 40 m/s to the west
    • D) 40 m/s to the east
15. 15.

    Two observers moving at different constant velocities relative to each other track an object accelerating along a straight line. Which kinematic quantity describing the object's motion will both observers measure to have the same value?

    • A) The acceleration of the object
    • B) The instantaneous velocity of the object
    • C) The displacement of the object over a given time interval
    • D) The position of the object at any instant
16. 16.

    A small object is released from rest from the ceiling of a vehicle moving forward at a constant horizontal speed in a straight line. Neglecting air resistance, which trajectories describe the motion of the falling object as observed by an observer inside the vehicle and by a stationary observer on the ground?

    • A) A straight vertical line for the observer inside the vehicle, and a parabolic curve for the observer on the ground
    • B) A parabolic curve for the observer inside the vehicle, and a straight vertical line for the observer on the ground
    • C) A straight vertical line for both the observer inside the vehicle and the observer on the ground
    • D) A parabolic curve for both the observer inside the vehicle and the observer on the ground
17. 17.

    When establishing a frame of reference to describe one-dimensional motion, an observer chooses a coordinate origin and a positive direction. Which of the following quantities depends directly on the location chosen for the coordinate origin?

    • A) The position of an object at a given instant
    • B) The displacement of an object during a time interval
    • C) The time interval elapsed between two events
    • D) The velocity of an object moving at constant speed
18. 18.

    Which of the following best defines a frame of reference as used in physics?

    • A) An absolute location in space that remains universally at rest relative to all celestial bodies
    • B) A coordinate system and standard of time against which the position and motion of an object are measured
    • C) The geometric path traced by a moving particle from its initial point to its final destination
    • D) The net unbalanced force that causes a change in the state of motion of an object
19. 19.

    A passenger sits stationary in a seat on a train traveling along a straight track at a constant speed. Which statement correctly describes the passenger's state of motion?

    • A) The passenger is at rest relative to the train and moving relative to the ground.
    • B) The passenger is at rest relative to both the train and the ground.
    • C) The passenger is moving relative to both the train and the ground.
    • D) The passenger is at rest in an absolute sense because they are not expending physical effort.
20. 20.

    Two observers measure the velocity of a moving cart and obtain different numerical values. Which statement correctly accounts for this difference in their measurements?

    • A) One of the observers must have used an improperly calibrated instrument or made an experimental error.
    • B) The true velocity of the cart can only be determined by an observer who is in an absolute state of rest.
    • C) Velocity is an absolute quantity that alters whenever an object moves across different spatial boundaries.
    • D) Motion is relative, so the measured velocity depends on the frame of reference chosen by each observer.